You are correct that there is only one drydock in the U.S. (really in the world) capable of constructing a nuclear powered aircraft carrier (Newport News Shipbuilding, Newport News, VA.). However both Norfolk Naval Shipyard (east coast) and Bremerton Naval Shipyard (west coast) have a drydock large enough to accommodate a Nimitz class carrier and the facilities to perform significant repairs.
When I was a kid living in Yokosuka, Japan, they had an enormous drydock there which was, I believe, big enough to put a carrier into.
I read where it was the same drydock that the IJN Shinano was built in (off a Yamato class hull) and she was sunk by the USS Archerfish.
Right after the war ended, the Archerfish was taken into that very same drydock for some emergency repairs, and there were a multitude of Japanese shipworkers all milling around, eyeing her with an open, sullen hostility...the very same workers who had built the IJN Shinano.
The captain of the Archerfish could see this was an uncomfortable situation, so he had a translator say the submarine was open for anyone who wanted to take a tour, and that broke the tension...they jumped at a chance to see the inside of an American submarine!
On a side note, when I lived in Japan, there was an accomplished plastic surgeon, Dr. Vasquez, living in the same building complex as my family (it was an old, gigantic parachute hangar they had converted into “condos”, probably eight in all). I was good friends with one of his sons.
My mother told me later that Dr. Vasquez was in high demand due to the huge influx of soldiers wounded in Vietnam who needed a plastic surgeon, and they flew them into Yokosuka all day long in those olive colored Hueys with the white square and red cross on the doors, landing at the helipad across from the Sullivans School...I looked up at those all day as they came in...every hour on the hour it seemed. They looked to my ten year old eyes like giant flying tadpoles
They had an enormous german shepherd, even to this day, the biggest one I have ever seen. (It wasn’t just because I was a kid, either, that it looked so big. Both of my parents in later years also confirmed it was a gigantic dog.)
Well, this dog was so big, that to exercise it, they would tie its leash to the side mirror of their Pontiac station wagon and drive around the neighborhood as the dog trotted beside the car. (honest, not making this up)
That dog scared the crap out of me. I generally wasn’t afraid of dogs, but...this beast was so effing big, and when the surgeon’s son (Randy?) and I would walk past him as he was tied up, he would just...look at you. Not like you were a threat...it seemed more like...you were food.
One day, the surgeon was walking the dog, and as they went past that massive (empty) drydock, for some reason, nobody knows why, the dog just took off and began running towards the drydock. Maybe it saw a seagull, or a rat, nobody knows. But the doctor, caught off guard, fell to the ground and was being dragged behind the dog, his wrist entangled in the loop of the leash.
He managed to extricate his hand, and the dog leaped over the edge and disappeared into the drydock! (This was all relayed to me by my parents and the doctor’s son)
The dog was apparently unharmed (I don’t know how, that drydock looked like it must have been 10 stories from the bottom to top) and there was a picture the next day in the Stars and Stripes of this huge drydock with a little speck of a dog all alone inside it at the bottom!